Population genetic structure and demographic history of Spodoptera frugiperda (Lepidoptera: Noctuidae): implications for insect resistance management programs

High levels of population admixture, including between corn- and rice-strains, were found in sampled populations. We showed that S. frugiperda immigrants will not necessarily cause an increase in LC₅₀ upon arrival in a new location but will assure the constant presence of resistance alleles in the area. Increases in LC₅₀ largely depend on the local pesticide management adopted in the areas. Our results indicate that pesticide resistance management must be adopted on a local or small regional scale.